GPC3 and hepatocellular carcinoma: Vδ1 T cells that were genetically modified to express 4-1BB/CD3 CAR targeting the oncofetal antigen glypican-3 and a constitutively secreted form of IL-15 exhibited superior proliferation and anti-tumor activity against hepatocellular carcinoma (HCC) lines and HCC subcutaneously engrafted in immunodeficient mice compared with their non-cytokine secreting counterparts (102).